Method of and apparatus for creating abnormal pressure in, and sealing hollow bodies



Sept. 17, 1929.

METHOD OF AND APPARATUS FOR CREATING ABNORMAL PRESSURE IN, AND SEALING HOLLOW BODIES Filed Feb. 13, 1924 A. c. BADGER Patented Sept. i 7, 1929' ARTHUR c. BADGER, NEWTON,

ME'riaoD OF AND- APPARATUS EoR cREATINo ABNORMAL PRESSURE IN,

SEALING HOLLOW. BODIES Application fil ed February 13, 1924.

f The object of the present invention is to provide a means for, and to accomplish the result of, hermetically sealing hollow articles wherein the internal pressure is different 5 from the external atmospheric pressure. Such articles therefore may be containers holding a fluid, whether liquid or gaseous, under a pressure greater than atmospheric, or they may be'exhausted of 'air, such as double walled bottles or jars in which the space between the inner and outer walls is vacuum.

One particular end which I have had in view in developing the present invention has been to provide metal cartridges or bottles containing air or other gas under high pressure, or a liquefied gas such as carbon dioxide, and so securely closed and sealed that loss of the enclosed pressure by leakage is im- 2 possible even after lapse of long periods of time after filling. Containers of the sort last indicated are well adapted for use in portable fire extinguishers, when mounted in such proximity to a piercing tool, having a handle at the outside of the extinguisher, and so arranged, that by manipulation of the tool the cartridge may be pierced or broken and the confined fluid liberated whereby to apply pressure upon the liquid contents of the extinguisher and forcibly expel such liquid for putting out 'a fire. Heretofore containers, or cartridges, of this sort have never been eifectively sealed. Although attempts have been made to put on the. market closed packages containing gas under pressure to be used in fire extinguishers, yet there has been no assurance that such closed packages would remain tight and retain the desired pressure of their contents throughout long periodsof time, but in fact many such containers have been found to have lost so much of their internal pressure, even a short time after being filled, as to be useless. A portable fire extinguisher is an emergency apparatus, designed to be charged and left at a place where it may be immediately available in case a fire should break out. Since the time when such an emergency may occur can never be forecast, the prime essential quality of the extinguisher is that long period thereafter.

MASSACBIUSETTS AND Serial No. 692,468. it shall be in serviceable condition not only immediately after being charged but for a Obviously an extinguisher equipped with a cartridge containing compressed gas is not a reliable apparatus if there is any possibility that the gas may leak out of the cartridge before the emergenoy arises when it is needed. Yet the gas filled capsules heretofore provided for this urpose have been so defective and have so often failed in emergency that they have been discredited with the informed their use has been disapproved y the fire underwriters.

My invention is concerned with metal cartridges of the sort above indicated, and also with metal vacuum bottles, that is, double walled containers with a vacuum space between the walls. My object in either case is to exclude possibility of leakage between the interior and exterior of the closed space within the article, whereby the initial condition of pressure or vacuum within this space may be maintained indefinitely. This object I have accomplished by autogenously sealing the article by the agency of heat electrically.

developed in the container and its closing member, and by causing these members to become fused together under pressure conditions which preclude any substantial departure from the desired internal pressure before the seal has been made perfect.

It should be understood that the foregoing reference to specific articles has been made for the purpose of more clearly explaining the nature of the invention, and without any intention of indicating the limits of the scope in which I claim protection. On the contrary I claim the apparatus phase of the invention for all uses to which it is capable of being applied and the process or method phase of the invention in connection with all articles of whatever nature or description which are capable of containing fluid under super atmospheric pressure. or of being exhausted of pressure, and of being sealed by fusion.

In the drawing I have shown an apparatus by the use of which my method may be carried out. This drawing also illustrates the principles of the apparatus part of the inublic, andvent-ion, but does not purport to show thetion of the same apparatus but taken on a plane at right angles to that of the section shown in Fig. 1.

Fig. 3 is a fragmentary cross section on line 3-3 of Fig. 1.

Fig. 4 is a detail view of a modification.

' Like reference characters designate the same parts wherever they occur in both figures.

A container to be filled and sealed is designated by the numeral 1. It is any cartridge or bottle made of material which can be weld- .ed electrically, preferably iron or steel. The nunmeral 2, in Fig. 1, represents a stopper also of weldable material, preferably sheet iron, drawn and shaped into cup form in such manner that it has a transverse end wall, a cylindrical portion 3 which fits within the neck of the bottle or'cartridge, and an external flange 4 at the junction between the end wall and cylindrical portion, which flange is adapted tooverlie the edge or lip surrounding the neck of the bottle when the stopper is fully inserted. One or more ports 5 are provided in the tubular cylindrical part of the stopper and are so located that when the stopper is partly inserted into the cartridge, as shown in Fig. 1, these ports are outside of the neck of the cartridge, but when the stopper is fully pushed in,-they are surrounded and covered by the neck of the cartridge. The metal from which the stopper is made is thick enough to withstand the pressure intended to be confined in the bottle; that is thick enough to preclude liability of the Although I have described the stopper as,

made of sheet metal drawn and pressed into the desired form, it should be understood that it may be made in other ways and by other methods, as for instance, by casting or molding the material of which it is made, while in a sufliciently fluid condition.

Also, although I have named iron or steel as the preferred material for making the body of the container and the stopper, it is gas may be delivered, and in which are contained suitable electrodes connected with a source of electric current and adapted to be so engaged with the cartridge and its stopper as to generate welding heat between the abutting surfaces of these parts.

The drawings show in somewhat diagrammatic form an operative construction of filling and. closing apparatus such as I have just described in general terms. The numeral 6 represents this apparatus as a whole. 7 represents a detachable plug or cap at one end of the apparatus which is screwed to the body of the apparatus and when removed leaves an opening through which the cartridge may be inserted and removed. This plug has a seat 8 to support the cartridge while being filled and sealed. 9 represents a gasket or other packing suitable to prevent leakage of the pressure contained within the filling apparatus. This plug or cap is typical of many specifically different structures which might be provided to support the cartridge and to close an opening through 'which the cartridge may be placed in and removed from the filling apparatus; although within the scope in which I claim protection the cartridge supporting function of the cap may be performed by other and difierent parts or agents.

The means for admitting air or other gas under pressure, or a liquefied gas, to the interior space of the filling apparatus, and conversely means for reducing the internal pressure of the apparatus when employed for exhausting a vacuum space and sealing such space in a double walled bottle or other hollow article, is typified by a threaded passage 10 to which a pipe may be connected. A pressure gauge 11 may also be connected with the apparatus to indicate the pressure applied therein.

The welding or heat generating part of the apparatus is typified by massive contact members 12 and 13 which together constitute one of the electrodes, and by a complemental contact member or electrode 14. The contact members 12 and 13 are shaped as jaws or clamps adapted to embrace the neck of the cartridge, or the wall near such neck, and to have an extended bearing thereon. They are connectedby wires 15 and 16 with one side of an electric circuit, whilethe complemental electrode 14 is connected with the other side of the circuit. The wires 15 and-16 areconfined in rigid sleeves or tubes 17 of insulating material which pass through stuffing boxes 18 in the sides of the main casing, and serve as means for supporting the electrode jaws and for adjusting them so as to bear closely upon the sides of the bottle-orcartridge 1. For the purposes of the present invention it may be assumed that such adjustment of the electrode jaws is effected manual- 1y, but it is to be understood that I may provide other means of any suitable character for supporting the electrode jaws and causing them to press closely against the sides of the cartridge. I

The complemental electrode 14 has .ari extended surface adapted to bear over the end of the stopper 2,. and preferably to overlie the entire area ofsuch stopper. It is secured to a conductor bar or wire 19 which is confined within an insulating sleeve or tube 20 which passes into the casingthrough a stuffing box 21 and is likewise adjustable manually, or otherwise, to place the electrode in and out of contact with the'cartridge stopper, and also to apply pressure to such stopper in order to force it fully into the cartridge. Both electrodes are of massive construction and have low electrical resistance, being preferably made of copper, asusual in electrical welding apparatus. 1

In the side of the casing, intermediate the sides through which the electrode supporting sleeves 17 pass, is an opening or window 22 covered by a transparent pane 23 which is preferably mounted in a removable manner by a suitable attaching ring 2/1 in which it is held by a retainer 25, such attaching ring being packed to prevent leakage. The purpose of the window is to enable the pro ress of the welding operation to be observe The window may also be used as an opening through which the cartridge may be inserted and removed, and it typifies means other than the plug or cap 7 for this pur ose.

The process of filling an tridges, which is carried out with the aid of an apparatus constructed substantially as hereinbefo're described,-may now be readily understood. The unfilled cartridge, in whichthe stopper has been partly inserted but left in a position where its ports 5 are outside of the mouth of the cartridge, is placed in the casing substantially as shown in the'drawings and is clamped between the contact members 12 and 13. After tightly closing the opening through which the cartridge was admitted, compressed air or other gas or liquefied carbon dioxide, or whatever fluidit may be with which the cartridge is to be charged, is then forced into the casing through the connection 10 provided for that purpose, and it fills the cartridge at the same pressure as that which exists within the casing. Then the electrode sealing car- 1 1 is advanced and is used as a pusher to force home the stopper 2 until the ports 5 in the sides of the stopper are covered and the lip e-bears against the rim of the cartridge. Gurrent being caused to. flow through the circuit of which the electrodes and the cartridge form a part, while pressure is maintained through the electrode 14, the contactin lip of the stopper and the rim ofthe cartridge are softened and welded together.

The welding operation takes place while the cartridge and its stopper are under an external pressure equal to that of the contents of the cartridge, whereby there is no possibility of part of the contents of the cartridge being lost after filling and before sealing. In

order to avoid possibility of loss of any of the contents of the cartridge due to expansionby heat in the welding operation and before the weld has solidified, the result of which might be a reduction ofthe pressure of the contents of the cartridge, afterjcooling, to less than the intended p ssure, I may increase the fluid pressure in he casing while the welding action takes place, by anamount equal to or exceeding that to which the welding heat raises the pressure of the cartridge contents.

Thus even though such contents may be momentarily heated and expanded, their escape V during welding is prevented by the superior pressure then existing outside of the car- I tridge.

When the c' lrtridge has been charged and sealed as above described, it may be removed from the casing and placed in the fire extinguisher or other apparatus with which it' is to be used, ready for instant use or for emergenc use at any time, or it may be stored away rea y to'be later produced and applied to its intended service. Whatever may be its immediate disposition, it will remain in servicea-ble condition for an indefinite time, being free from liability of losing any of its contained pressure by leakage, provided 1t is protected from corrosion and accidental damage. But it may be used at any time and the full pressure of its contained gas or liquid availed of by placing it in the fire ex.- tinguisher, or other apparatus with which it is intended to be used and there puncturing its stopper. Y

The method of exhausting an. internal space in a hollow article and sealing such space, is identical in principle with the meth od just described, although it is the reverse 0 such method in the respect that the air is exhausted from the apparatus and from the hollow article therein. The gauge then used is of a character w 'ch measures pressure below atmospheric. But when the air has been pulled out to the desired degree of vacuum,

walled bottle, the stopper or cover for the vacuum space would be of specifically diflerent shape, and possibly different in other characteristics from the stopper 2 previously described, but as myinvention is concerned with principles and not with specific forms of thearticles operated upon, this fact is of no importance to my claims.

A specifically different form of stopper is shown in Fig. 4, in conjunction with electrodes of modified construction. The stopper 2 is essentially a cover, the outline of which conforms to the mouth of the hollow article, whether such mouth is circular, annular, or of any other shape or character. The electrode 14L may be recessed on its active face to provide a pocket adapted to hold the stopper, when separated from the hollow body, in correctly centered relation ready to be placed over the open mouth of the body and in contact with the bounding walls of the mouth.

The electrodes or contact jaws 12 and 13 are substantially like the electrodes 12 and 13 except that they are extended to envelope SL1l')St311tl1IllV the entire surface of the hollow body, whereby to reduce to the minimum resistance to flow of current between the body and electrodes, and to concentrate the heatgenerating resistance at the junction between the body and the cover, where welding is required to take place. These body-grasping electrodes may be mountedin the chamber structure as already described, or otherwise. Itis not essential that the electrical leads to the body-engaging electrodes of either form be insulated from the chamber walls, provided the opposite electrode and its lead are insulated, since the current used for electric welding is of very low voltage, wherefore other modes of connecting either of the opposed electrodes with the source of electricity from those previously described may be used.

Stated in general terms, the invention in either of its aspects, that is whether concerned with confining fluid under super atmospheric pressure or excluding atmospheric pressure from a closed space, consists in creating the desired pressure within the enclosed space of a hollow metal article, and then sealing by electric fusion the entrance to the interior space of the article, while such article is ex- .posed externally to substantially the same pressure conditions as its interior space.

hat I claim and desire to secure by Letters Patent is: a I

l. The method of sealing metallic hollow bodies having an internal pressure difi'erent from the atmosphere which consists in placing an open hollow metal body, or the mouth thereof, and a separate metal cover for such mouth, in an enclosed chamber, creating in said chamber a fluid pressure c0nd1t10n different from the atmospheric pressure, and

electrically welding said cover to said hollow a separate cover for such mouth, also made of electrically conductive material, in an enclosed chamber, closing said chamber to prevent flow of fluid between its interior and the'outer tlt-lllOSPllOl'G, creating in said chamber a "fluid pressure condition difl'erent from the atmospheric pressure, bringing said cover into contact with the mouth of said hollow body and causing an! electric current to flow through the body and cover in sufiicient quantity to heat the contacting points of the body and cover to Welding temperature and condition, and then forcing the body and cover together into welded union while the fluid pressure condition within said chamber persists. 3. The method of filling and sealing containcrs of fluid under pressure which consists in placing a container and a separate stopper with liquefied gas under pressure which consists in placing at least the open mouth portion of such cartridge within a closed chamber and arranging a metal cover in the chamber adjacent tosaid mouth but not in position to close the same, closing said chamber against escape of the confined fluid, forcing the liquefied gas under pressure into said chamber and the interior of said cartridge, causing electric current to'flow through said cartridge and cover while the same.are in contact with one another in quantity sufiicient to bring their contacting portions to a temperature and softness suitable for welding and while in this condition forcing the cartridge and cover together to complete a welding joint between them, all while the contacting parts of the cartridge and cover are enveloped, and surrounded by the liquefied gas under pressure.

5. The method of filling metallic cartridges with liquefied carbon dioxide gas and sealing such containers which consists in placing at least the mouth portion of an open metal cartridge in an enclosed chamber, tightly closing said chamber to prevent es-. cape of the confined liquid carbon dioxide during filling of the cartridge, forcing liquid carbon dioxide under high pressure into said chamber and the interior of the carelectric current to flow tridge, causing through said cartrldge and a metallic cover placed over the mouth thereof, such current being of a quality and amount sufiicient to raise the temperature of the cartridge and cover to welding heat at the junction between them, and pressing the heated body and cover together to form a weld; all while enveloped in the liquid carbon dioxide at the prescribed filling pressure. w

(3. An apparatus for sealing hollow metallic bodies with an internal pressure different from the atmosphere, which comprises a casing having a removable closure, a fluid conduit in connection with said casing, and complemental welding electrodes in said chamber.

7 An apparatus for closing hollow metallic bodies having an internal'pressure diiferent from the atmosphere, which comprises a casing having a removable closure and provisions for flow of fluid, and complemental welding electrodes in said chamber, said electrodes being constructed and arranged with provision for movement between them in such manner as to engage the parts of an ope hollow metallic bodywhich surround the'opening of such body and to close and weld such parts together.

8. An apparatus for closing hollow me-' tallic bodies having pressure therein different from the atmosphere, which comprises a casing and a removable closure therefor, having an interior chamber and provisions for flow of fluid, and complemental electric welding electrodes arranged and organized to engage respectively an open hollow metallic body and a cover for the opening of suchbody, andsaid electrodes being mounted with provision for relative movement whereby to close and press said cover against said body.

9. A filling and sealing apparatus comprising a casing having an interior chamber adapted to'lreceive a metallic cartridge and a charge of compressed or liquefied gas under pressure, means for conducting electric current into said casing and through the cartridge held therein, and a complemental electrical conductor and electrode entering said casing and being movable therein by force externally applied, said casing and electrode together being adapted to confine an open cartridge and a cover therefor between them and to apply endwise closing pressure between the cartridge and the cover.

10. A filling and sealing apparatus comprising a casing adapted to receive a container of 'compressed fluid, complem tal electrical contact members adapted to gmtrode of opposite sign from said contact members, adapted to engage the stopper of such container, the last named electrode being movable whereby to press the stopper against the rim of the container, and means for admitting compressed fluid to the interior of said casing.

11, An apparatus for sealing metallic bottles having a pressure therein different from the atmosphere, comprising a chamber having a closable entrance for the mouth of such .a bottle, and having also an external flow connection, and complemental massive electrical cont-act members arranged in contact withthe bottlenear its mouth and with a closing member for such month, arranged to press the closing member against the rim of said month; said contact members being in circuit with a source of electric current of sufiicient amount to generate welding heat at. the junction between the bottle and its closing member.

In testimony whereof I have alfiXed my signature.

ARTHUR C. BADGER. 

